Air Conditioning Device, in particular for a Rail Vehicle

ABSTRACT

An air conditioning device is provided. The air conditioning device includes a primary circuit in which a refrigerant circulates, the primary circuit including an evaporator, and a first secondary circuit in which a first fluid circulates. The first fluid passes through the evaporator to exchange heat therein with the refrigerant. The first secondary circuit includes at least one first heat exchanger in which the first fluid exchanges heat with the air. The air conditioning device further includes at least one first compartment in which the primary circuit is housed, an air treatment zone, formed outside the first compartment and intended to communicate with the inside air, and in which the first heat exchanger is housed, and at least one sealed wall, separating the compartment from the air treatment zone. A railway vehicle having an air conditioning device is also provided.

Priority is hereby claimed to French Patent Application No. 12 58595 filed on Sep. 13, 2012, the entire disclosure of which is hereby incorporated by reference herein.

The present invention relates to an air conditioning device, in particular for conditioning the inside air of a passenger compartment or premises. In particular, the invention relates to an air conditioning device for a rail vehicle passenger compartment, but it may be used for any other type of vehicle (road, sea or air) requiring air conditioning, or for any type of premises.

BACKGROUND

EP 1 662 212 purportedly discloses an air conditioning system which can control a refrigerant flow rate to a heat exchanger exchanging heat with room air to be optimum. The system can be installed on a multistory building without limitation of a height of the building as far as a capacity of the pump permits.

EP 2 461 109 purportedly discloses a cold/hot water supply apparatus which determines whether fluid which flows out of a first heat exchanger should be made to flow toward a third heat exchanger or the first heat exchanger based on temperature of the fluid detected by a temperature sensor disposed on the first heat exchanger.

JP 2006029744 purportedly discloses an air conditioner with a centralized refrigerating circuit including refrigerating devices, an indoor circuit including a fan coil unit and a relay circuit including intermediate heat exchangers. The indoor circuit is connected to the centralized refrigerating circuit by the intermediate heat exchanger and the refrigerant in an amount of equal to or lower than the tolerable refrigerant concentration of the room wherein it is installed is filled in the indoor circuit.

DE 2417158 purportedly discloses air conditioning particularly for railway vehicles. FR 2902864 purportedly discloses a controlled ambience device, such as a wine cellar or air-conditioning device, which has a main enclosure, a main loop, an auxiliary loop and a heat exchanger.

Already known from the state of the art is an air conditioning device including a circuit in which a refrigerant circulates, traditionally comprising a compressor, a condenser, an expander and an evaporator.

The refrigerant is typically a phase change fluid of the HFC (hydrofluorocarbon) type, for example a refrigerant known by the name R134a, R407c, R410, R744 or R152a. Such a refrigerant is relatively polluting and/or flammable.

In such an air conditioning device, the evaporator is generally passed through by the air that enters the passenger compartment (or premises) to be air-conditioned. In other words, the refrigerant circuit is arranged near the passenger compartment, such that in case of leak, refrigerant may flow into the passenger compartment (or premises).

Yet the intrusion of refrigerant in the passenger compartment is undesirable, in particular when, as previously mentioned, the refrigerant is polluting and/or flammable.

SUMMARY OF THE INVENTION

An object of the present invention includes providing an air conditioning device that may avoid the risks of leaks in the passenger compartment.

The present invention provides an air conditioning device, intended for inside air conditioning in at least one passenger compartment, in particular a rail vehicle passenger compartment, or premises. The air conditioning device includes a primary circuit, in which a refrigerant circulates, and which includes an evaporator, a first secondary circuit, in which a first fluid circulates, said first fluid passing through the evaporator to exchange its heat therein with the refrigerant, the first secondary circuit comprising at least one first heat exchanger in which said first fluid exchanges its heat with the air. The air conditioning device further including at least one first compartment, in which the primary circuit is housed, an air treatment zone, formed outside the compartment and intended to communicate with the inside air, and in which the first heat exchanger is housed, and at least one sealed wall, separating the compartment from the air treatment zone.

Thus, the primary circuit is completely housed in the compartment, which is sealably separated from the air treatment zone, and therefore from the passenger compartment. In case of a leak on the primary circuit, the refrigerant flows into the compartment, but does not enter the passenger compartment, since the wall is sealed.

Optionally, an air conditioning device according to the invention may include one or more of the following features, considered alone or according to any technically possible combinations:

The primary circuit includes a compressor, a condenser and an expander, all, in addition to the evaporator, being housed in the compartment.

The compressor, condenser, expander and evaporator are arranged on a shared support.

The shared support is removable from the compartment.

The primary circuit includes rigid circulation ducts for the refrigerant, respectively connecting the condenser to the expander, the expander to the evaporator, the evaporator to the compressor, and the compressor to the condenser, each rigid duct preferably having a length smaller than 50 cm.

The air conditioning device includes a second secondary circuit, in which a second fluid circulates, said second fluid passing through the condenser to exchange its heat therein with the refrigerant, said second circuit including at least one second heat exchanger, in which the second fluid exchanges its heat with the outside air.

The second secondary circuit includes a second pump for circulating the second fluid, said second pump being housed in the compartment.

The first secondary circuit includes a first pump for circulating the first fluid, said first pump being housed in the compartment.

The first secondary circuit includes ducts connecting the evaporator to the first heat exchanger, at least one of said ducts passing through the sealed wall, a sealing gasket being provided between said duct and said sealed wall.

The air conditioning device includes a second compartment forming the air treatment zone, said second compartment being open so as to communicate with the inside air.

The present invention also provides a rail vehicle, in particular a tramway vehicle, including a passenger compartment, comprising an air conditioning device for the inside air of the passenger compartment as recited above.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood upon reading the following description, provided solely as an example and done in reference to the appended figures, in which:

FIG. 1 diagrammatically shows an air conditioning device according to a first example embodiment of the present invention, and

FIG. 2 diagrammatically shows an air conditioning device according to a second example embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows an air conditioning device 10, intended for inside air conditioning in at least one passenger compartment, for example a rail vehicle passenger compartment. Alternatively, this air conditioning device may be intended for inside air conditioning in a passenger compartment of any other type of vehicle, or in any type of premises.

The air conditioning device 10 includes a primary circuit 12, in which a refrigerant circulates. Said refrigerant exchanges heat with the air through a secondary circuit, called first secondary circuit 14.

The primary circuit 12 traditionally includes a compressor 18, a condenser 20, an expander 22 and an evaporator 24.

The primary circuit 12 further includes refrigerant circulation ducts 26, in particular: a duct 26A connecting the condenser 20 to the expander 22, a duct 26B connecting the expander 22 to the evaporator 24, a duct 26C connecting the evaporator 24 to the compressor 18, and a duct 26D connecting the compressor 18 to the condenser 20. Preferably, the ducts 26 are rigid.

Traditionally, the refrigerant is a phase change fluid of the HFC type, for example known under the name R134a, R407c, R410, R744 or R152a.

The first secondary circuit 14, in which a first fluid circulates, passes through the evaporator 24 such that the first fluid exchanges its heat therein with the refrigerant of the primary circuit 12. This first secondary circuit 14 also includes at least one first heat exchanger 30, in which said first fluid exchanges its heat with air, and a first pump 32 to circulate the first fluid in said first secondary circuit 14.

The first secondary circuit 14 further includes ducts 34 serially connecting the evaporator 24, the first heat exchanger 30 and the first pump 32, so as to form a loop.

It will be noted that, when the air conditioning device 10 is installed for use, the first heat exchanger 30 communicates with the inside air of the passenger compartment or the premises to be air conditioned, which then forms a cold source for the air conditioning device 10.

Furthermore, the condenser 20 forms a heat exchanger communicating with outside air, which then forms a hot source for the air conditioning device 10.

Preferably, the first fluid circulating in the first secondary circuit 14 is a liquid with a high heat capacity and high density, which makes it possible to reduce the volume of fluid necessary to perform the heat exchange. This liquid has a low pressure loss in particular at low temperatures so as not to be too viscous, and a low freezing point, ideally below −40° C., or at least below −20° C., so as not to freeze in the winter. For example, the first fluid is a mixture of monoethyleneglycol and water, or a mixture of the “TIFOXIT” type.

The operation of an air-conditioning device according to this first embodiment of the invention follows.

The cycle of the refrigerant in the first primary circuit 12 is traditional and known in itself.

At the inlet of the compressor 18, the refrigerant is generally in gaseous phase. The refrigerant is compressed therein (its pressure typically goes from 3 bars to 20 bars, for example) and becomes very hot, approximately 60° C., for example.

In passing in the condenser 20, the refrigerant cools, then condenses. It then goes from a gaseous phase to a liquid phase, without changing temperature. At the outlet of said condenser 20, the refrigerant is in the liquid phase, at a high temperature and high pressure.

The refrigerant next passes into the expander 22, and expands adiabatically. It cools, until its pressure returns to 3 bars and its temperature is approximately 0° C. The refrigerant then forms a liquid/gaseous mixture next passing into the evaporator 24.

In said evaporator 24, the refrigerant heats again by capturing the heat from the first fluid that circulates in the first secondary circuit 14. The refrigerant then changes phase and becomes completely gaseous before again returning into the compressor 18.

In the first secondary circuit 14, the first fluid takes on calories from the air to be air conditioned (cold source) in the first heat exchanger 30, and then provides those calories to the refrigerant in the evaporator 24.

In parallel, the outside air (hot source) takes on calories from the refrigerant in the condenser 20.

It will be noted that such an air conditioning device 10 may have a relatively small bulk for the primary circuit 12.

In particular, the evaporator 24 is intended for exchanges with the first fluid rather than with air, and therefore requires a smaller heat exchange surface. This evaporator 24 therefore has a smaller bulk than an evaporator provided for a heat exchange with the air.

Due to this smaller bulk, the evaporator 24 may be arranged closer to the compressor 18, which makes it possible to reduce the length of the ducts 26B, 26C, and to limit the bulk of the primary circuit 12 in its entirety.

Thus, advantageously, the length of each duct 26B, 26C is smaller than 50 cm, for example.

It will be noted that, due to this reduced bulk, the primary circuit 12 contains a smaller quantity of refrigerant, generally less than 4 kg, for example.

Advantageously, the compressor 18, the condenser 20, the expander 22 and the evaporator 24 are arranged on a shared support 28. In other words, the primary circuit 12 in its entirety is secured to the shared housing 28, and can therefore be handled in its entirety for assembly or disassembly in the air conditioning device 10.

Thus, for maintenance of the air conditioning device 10, the primary circuit 12 may be disassembled in a single unit without its components (i.e., the compressor 18, condenser 20, expander 22 and evaporator 24) being separated. Thus, it is not necessary to disassemble ducts 26 containing refrigerant, with the result that the disassembly operation of the primary circuit 12 may be carried out by a maintenance worker, even if that worker is not qualified to handle refrigerant circuits.

When the air conditioning device 10 is assembled on the vehicle, it undergoes vibrations and various movements as the vehicle travels. Owing to the shared support 28, all of the components of the primary circuit 12 then simultaneously undergo the same vibrations and movements. Thus, since the movements and vibrations of said components 18, 20, 22, 24 are similar; no stress is created on the ducts 26, which therefore reduces the risks of wear and leakage on those ducts 26.

The air conditioning device 10 includes at least one first compartment 42, in which the primary circuit 12 is housed, therefore in particular the compressor 18, condenser 20, expander 22 and evaporator 24.

The air conditioning device 10 also includes an air treatment zone 44, arranged outside the compartment 42, and intended to communicate with the inside air, and in which the first heat exchanger 30 is housed.

Preferably, the first pump 32 is housed in the compartment 42. Alternatively, the first pump 32 may be housed outside the compartment 42, for example in the air treatment zone 44.

Lastly, it will be noted that the condenser 20 is housed inside the compartment 42. Thus, a grate 48 is provided across from the condenser 20, to allow said condenser 20 to communicate with the outside air.

At least one sealed wall 46 separates the compartment 42 from the air treatment zone 44. Thus, in case of refrigerant leakage from the primary circuit 12, the latter flows into the compartment 42, and does not flow into the air treatment zone 44 owing to the sealed wall 46. The air treatment zone 44 being intended to communicate with the passenger compartment or premises, it will be noted that the passenger compartment or premises are thus protected from pollution by the refrigerant.

Since the first heat exchanger 30 is housed in the air treatment zone 44 and the evaporator 24 is housed in the compartment 42, the ducts 34 of the first secondary circuit pass through the sealed wall 46. A sealing gasket is then provided around each duct 34 in the passage through the sealed wall 46, so as to preserve sealing of that wall 46.

Preferably, a relatively compact primary circuit 12 is provided. The compactness of the primary circuit 12 may make it possible to limit the risk of leakage. In fact, due to the limited quantity of refrigerant contained by a compact primary circuit 12, the risks of the sealing wall 46 giving way under the pressure of the refrigerant having leaked into the compartment 42 may be very limited. In other words, due to this small quantity of refrigerant, it appears that the sealed wall 46 is sufficient to prohibit refrigerant leaks from the compartment 42 to the air treatment zone 44.

Advantageously, the shared support 28 is removable from said compartment 42. Thus, the primary circuit 12 may be easily disassembled for maintenance purposes, simply by disconnecting the ducts 34 from the first secondary circuit of the evaporator 24.

According to another preferred embodiment, the air conditioning device 10 includes a second compartment forming the air treatment zone 44. This second compartment is then opened so as to communicate with the inside air of the passenger compartment or premises.

FIG. 2 shows an air conditioning device 10 according to a second preferred embodiment of the invention. In FIG. 2, the elements similar to those previously described are designated using identical references.

According to this second embodiment, the air conditioning device 10 is of the double indirect type. In other words, the air conditioning device 10 includes, in addition to the primary circuit 12 in which the refrigerant circulates, two intermediate circuits, called first secondary circuit 14 and second secondary circuit 16, said refrigerant exchanging heat with the air via secondary circuits 14, 16.

The first secondary circuit 14 is substantially identical to that which was described in reference to FIG. 1.

Furthermore, the second secondary circuit 16, in which a second fluid circulates, passes through the condenser 20, such that the second fluid exchanges its heat therein with the refrigerant from the primary circuit 12. This second secondary circuit 16 also includes at least one second heat exchanger 36, in which the second fluid exchanges its heat with outside air, and a second pump 38 for circulating the second fluid in said second secondary circuit 16.

The second secondary circuit 16 further includes ducts 40 serially connecting the second heat exchanger 36, the condenser 20 and the second pump 38, so as to form a loop.

It will be noted that, when the air conditioning device 10 is installed for use, the second heat exchanger 36 communicates with outside air, which then forms a hot source for the air conditioning device 10.

Preferably, the first and second fluids respectively circulating in the first 14 and second 16 secondary circuits are liquids with a high heat capacity and high density, to reduce the volume of fluid necessary to perform the heat exchange. These liquids have a low pressure loss in particular at low temperatures so as not to be too viscous, and a low freezing point, ideally below −40° C., or at least below −20° C., for example, so as not to freeze in the winter. For example, the first and second fluids are monoethyleneglycol and water mixtures, or mixtures of the “TIFOXIT” type.

The operation of a doubly indirect air conditioning device like that of the present invention is provided below.

The cycle of the refrigerant in the primary circuit 12 is traditional and known in itself

At the inlet of the compressor 18, the refrigerant is generally a gaseous phase. The refrigerant is compressed therein (its pressure typically goes from 3 bars to 20 bars, for example) and becomes very hot, approximately 60°, for example.

In passing through the condenser 20, the refrigerant cools, and then condenses. It then goes from a gaseous phase to a liquid phase, without changing temperature. At the outlet of said condenser 20, the refrigerant is in liquid phase, at a high temperature and high pressure.

The refrigerant then passes into the expander 22, and expands adiabatically. It cools, until its pressure returns to 3 bars and the temperature is approximately 0° C. The refrigerant then forms a liquid/gaseous mixture next passing into the evaporator 24.

In said evaporator 24, the refrigerant heats while capturing heat from the first fluid that circulates in the first secondary circuit 14. The heat then changes phase and again becomes completely gaseous before reentering the compressor 18.

In the first secondary circuit 14, the first fluid takes on calories from the air to be air conditioned (cold source) in the first heat exchanger 30, then provides those calories to the refrigerant in the evaporator 24.

In the second secondary circuit 16, the second fluid takes on calories from the refrigerant in the condenser 20, and then provides those calories to the outside air (hot source) in the second heat exchanger 36.

It will be noted that such a double indirect air conditioning device may limit the bulk of the primary circuit.

In particular, the evaporator 24 and the condenser 20 are intended for exchanges with the first and second fluids, respectively, rather than with the air, and therefore require a smaller heat exchange surface. This evaporator 24 and condenser 20 therefore have a smaller bulk then the evaporators and condensers provided for heat exchange with the air.

Due to the smaller bulk, the evaporator 24 and the condenser 20 can be arranged as close as possible to the compressor 18, which makes it possible to reduce the length of the ducts 26, and to limit the bulk of the primary circuit 12 in its entirety.

Thus, advantageously, the length of each duct 26 is smaller than 50 cm, for example.

It will be noted that, due to this reduced bulk, the primary circuit 12 contains a smaller quantity of refrigerant, generally less than 4 kg, or even less than 2 kg, for example.

Preferably, the first pump 32 and the second pump 38 are both housed in the compartment 42. Alternatively, at least one of these pumps, for example the first pump 32, could be housed outside the compartment 42, for example in the air treatment zone 44.

Lastly, it will be noted that the second heat exchanger 36 may be housed inside the compartment 42. In that case, a grate 48 is provided across from the second heat exchanger 36, to allow said second heat exchanger 36 to communicate with the outside air. Alternatively, the second heat exchanger 36 may be arranged outside the compartment 42.

It will be noted that the compactness of the primary circuit 12 makes it possible to limit the risk of leaks. In fact, due to the limited quantity of refrigerant contained by the primary circuit 12, the risks of the sealed wall 46 giving way under the pressure of refrigerant having leaked into the compartment 42 may be very limited. In other words, due to the small quantity of refrigerant, it appears that the sealed wall 46 is sufficient to prohibit refrigerant leaks from the compartment 42 into the air treatment zone 44.

Advantageously, the shared support 28 is removable from said compartment 42. Thus, the primary circuit 12 may be easily disassembled for maintenance reasons, simply by disconnecting the ducts 34 of the first secondary circuit from the evaporator 24, and the ducts 40 of the second secondary circuit 16 from the condenser 20.

It will be noted that the invention is not limited to the embodiment previously described, but to show various alternatives without going beyond the scope of the claims. In particular, the air conditioning device could include a more complex primary circuit, including several paths and valves for alternately connecting the condenser 20 to the first secondary circuit 14 and the evaporator 24 to the second secondary circuit 16, and thus to invert the hot and cold sources. 

What is claimed is:
 1. An air conditioning device for inside air conditioning in at least one passenger compartment of a rail vehicle passenger compartment, or premises, the air conditioning device comprising: a primary circuit, in which a refrigerant circulates, the primary circuit including an evaporator; a first secondary circuit in which a first fluid circulates, the first fluid passing through the evaporator to exchange heat therein with the refrigerant, the first secondary circuit including at least one first heat exchanger in which the first fluid exchanges heat with inside air; at least one first compartment housing the primary circuit; an air treatment zone, formed outside the at least one first compartment, to communicate with inside air, and housing the first heat exchanger; and at least one sealed wall separating the at least one first compartment from the air treatment zone.
 2. The air conditioning device according to claim 1, wherein the primary circuit includes a compressor, a condenser and an expander, all, in addition to the evaporator, being housed in the first compartment.
 3. The air conditioning device according to claim 2, wherein the compressor, condenser, expander and evaporator are arranged on a shared support.
 4. The air conditioning device according to claim 3, wherein the shared support is removable from the first compartment.
 5. The air conditioning device according to claim 3, wherein the primary circuit includes rigid circulation ducts for the refrigerant, respectively connecting the condenser to the expander, the expander to the evaporator, the evaporator to the compressor, and the compressor to the condenser, each rigid duct having a length smaller than 50 cm.
 6. The air conditioning device according to claim 2, including a second secondary circuit, in which a second fluid circulates, the second fluid passing through the condenser to exchange heat therein with the refrigerant, the second secondary circuit including at least one second heat exchanger, in which the second fluid exchanges heat with outside air.
 7. The air conditioning device according to claim 6, wherein the second secondary circuit includes a second pump for circulating the second fluid, the second pump being housed in the first compartment.
 8. The air conditioning device according to claim 1, wherein the first secondary circuit includes a first pump for circulating the first fluid, the first pump being housed in the first compartment.
 9. The air conditioning device according to claim 1, wherein the first secondary circuit includes a plurality of ducts connecting the evaporator to the first heat exchanger, at least one of the ducts passing through the sealed wall, a sealing gasket being provided between the at least one duct and the sealed wall.
 10. The air conditioning device according to claim 1, further comprising a second compartment forming the air treatment zone, the second compartment being open so as to communicate with the inside air.
 11. A rail vehicle comprising: a passenger compartment; and an air conditioning device for inside air of the passenger compartment, the air conditioning device including: a primary circuit in which a refrigerant circulates, the primary circuit including an evaporator; a first secondary circuit in which a first fluid circulates, the first fluid passing through the evaporator to exchange heat therein with the refrigerant, the first secondary circuit including at least one first heat exchanger in which the first fluid exchanges heat with inside air; at least one first compartment housing the primary circuit; an air treatment zone, formed outside the at least one first compartment, to communicate with inside air, and housing the first heat exchanger; and at least one sealed wall separating the at least one first compartment from the air treatment zone.
 12. The rail vehicle according to claim 11 wherein the rail vehicle is a tramway vehicle. 